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Re: Evaluation of Renal Masses With Contrast-Enhanced Ultrasound: Initial Experience
Urological Survey
Urological Oncology: Renal, Ureteral and Retroperitoneal Tumors Re: Evaluation of Renal Masses With Contrast-Enhanced Ultrasound: Initial Experience S. Gerst, L. E. Hann, D. Li, M. Gonen, S. Tickoo, M. J. Sohn and P. Russo Department of Radiology, Breast and Imaging Center, Memorial Sloan Kettering Cancer Center, New York, New York AJR Am J Roentgenol 2011; 197: 897–906.
Objective: Nearly 25% of solid renal tumors are indolent cancer or benign and can be managed conservatively in selected patients. This prospective study was performed to determine whether preoperative IV microbubble contrast-enhanced ultrasound can be used to differentiate indolent and benign renal tumors from more aggressive clear cell carcinoma. Subjects and Methods: Thirty-four patients with renal tumors underwent preoperative gray-scale, color, power Doppler, and octafluoropropane microbubble IV contrast-enhanced ultrasound. Three blinded radiologists reading in consensus compared rate of contrast wash-in, grade and pattern of enhancement, and contrast washout compared with adjacent parenchyma. Contrast ultrasound findings were compared with surgical histopathologic findings for all patients. Results: The 34 patients had 23 clear cell carcinomas, three type 1 papillary carcinomas, one chromophobe carcinoma, one clear rare multilocular low-grade malignant tumor, two unclassified lesions, three oncocytomas, and one benign angiomyolipoma. The combination of heterogeneous lesion echotexture and delayed lesion washout had 85% positive predictive value, 43% negative predictive value, 48% sensitivity, and 82% specificity for predicting whether a lesion was conventional clear cell carcinoma or another tumor. Diminished lesion enhancement grade had 75% positive predictive value, 81% negative predictive value, 55% sensitivity, and 91% specificity for non-clear cell histologic features, either benign or low-grade malignant. Combining delayed washout with quantitative lesion peak intensity of at least 20% of kidney peak intensity had 91% positive predictive value, 40% negative predictive value, 63% sensitivity, and 80% specificity in the prediction of clear cell histologic features. Conclusion: Ultrasound features of gray-scale heterogeneity, lesion washout, grade of contrast enhancement, and quantitative measure of peak intensity may be useful for differentiating clear cell carcinoma and non-clear cell renal tumors. Editorial Comment: The authors report prediction of histological tumor type with the use of microbubble contrast infusion during ultrasound to measure patterns of blood flow within renal masses. The article is provocative, as I believe that advances in imaging will change the way in which we manage solid malignancy in the near future. The ability to accurately determine tumor type in a noninvasive manner clearly has a substantial impact on our treatment paradigms, particularly in the era of targeted therapy. The proposed technique carries a high positive predictive value but the reported negative predictive value and sensitivity are too low to influence management significantly. Presumably these measures could be improved through refinement. It is important always to keep in mind the broad applicability of imaging platforms. An intrinsic difficulty with broad application of ultrasound based diagnostics is the considerable operator variability in study technique and interpretation. In the case of ultrasound, interoperator variability is probably much greater than with cross-sectional imaging, although the cost of the study is much less. Samir S. Taneja, M.D.
0022-5347/12/1874-1220/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
1220
www.jurology.com
AND
RESEARCH, INC.
Vol. 187, 1220-1227, April 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.12.088
Urological Oncology: Renal, Ureteral and Retroperitoneal Tumors Re: Evaluation of Renal Masses With Contrast-Enhanced Ultrasound: Initial Experience S. Gerst, L. E. Hann, D. Li, M. Gonen, S. Tickoo, M. J. Sohn and P. Russo Department of Radiology, Breast and Imaging Center, Memorial Sloan Kettering Cancer Center, New York, New York AJR Am J Roentgenol 2011; 197: 897–906.
Objective: Nearly 25% of solid renal tumors are indolent cancer or benign and can be managed conservatively in selected patients. This prospective study was performed to determine whether preoperative IV microbubble contrast-enhanced ultrasound can be used to differentiate indolent and benign renal tumors from more aggressive clear cell carcinoma. Subjects and Methods: Thirty-four patients with renal tumors underwent preoperative gray-scale, color, power Doppler, and octafluoropropane microbubble IV contrast-enhanced ultrasound. Three blinded radiologists reading in consensus compared rate of contrast wash-in, grade and pattern of enhancement, and contrast washout compared with adjacent parenchyma. Contrast ultrasound findings were compared with surgical histopathologic findings for all patients. Results: The 34 patients had 23 clear cell carcinomas, three type 1 papillary carcinomas, one chromophobe carcinoma, one clear rare multilocular low-grade malignant tumor, two unclassified lesions, three oncocytomas, and one benign angiomyolipoma. The combination of heterogeneous lesion echotexture and delayed lesion washout had 85% positive predictive value, 43% negative predictive value, 48% sensitivity, and 82% specificity for predicting whether a lesion was conventional clear cell carcinoma or another tumor. Diminished lesion enhancement grade had 75% positive predictive value, 81% negative predictive value, 55% sensitivity, and 91% specificity for non-clear cell histologic features, either benign or low-grade malignant. Combining delayed washout with quantitative lesion peak intensity of at least 20% of kidney peak intensity had 91% positive predictive value, 40% negative predictive value, 63% sensitivity, and 80% specificity in the prediction of clear cell histologic features. Conclusion: Ultrasound features of gray-scale heterogeneity, lesion washout, grade of contrast enhancement, and quantitative measure of peak intensity may be useful for differentiating clear cell carcinoma and non-clear cell renal tumors. Editorial Comment: The authors report prediction of histological tumor type with the use of microbubble contrast infusion during ultrasound to measure patterns of blood flow within renal masses. The article is provocative, as I believe that advances in imaging will change the way in which we manage solid malignancy in the near future. The ability to accurately determine tumor type in a noninvasive manner clearly has a substantial impact on our treatment paradigms, particularly in the era of targeted therapy. The proposed technique carries a high positive predictive value but the reported negative predictive value and sensitivity are too low to influence management significantly. Presumably these measures could be improved through refinement. It is important always to keep in mind the broad applicability of imaging platforms. An intrinsic difficulty with broad application of ultrasound based diagnostics is the considerable operator variability in study technique and interpretation. In the case of ultrasound, interoperator variability is probably much greater than with cross-sectional imaging, although the cost of the study is much less. Samir S. Taneja, M.D.
0022-5347/12/1874-1220/0 THE JOURNAL OF UROLOGY® © 2012 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION
1220
www.jurology.com
AND
RESEARCH, INC.
Vol. 187, 1220-1227, April 2012 Printed in U.S.A. DOI:10.1016/j.juro.2011.12.088